96 



THE OAK 



lets clothed by a fungus mycelium ; the mycelium is 

 found as a thin sheet of closely- woven hyphae continuous 

 over the whole of the tip, and sending processes in 

 between the cells of the dermatogen, but not into the 



FIG. 25. Longitudinal section of the tip of one of the 

 roots marked ra in fig. 7, the outer layers of which are 

 infested with fungus hyphse, /(mycorhiza) ; r.o, root- 

 cap ; m, embryonic tissue from which all originates ; P, 

 pith ; sp, spiral vessels of the primary xylem ; c, cortex. 



cavities of the cells nor deeper into the tissues. Loose 

 hyphaB also radiate into the soil around, and often simulate 

 the root-hairs of other plants, which, in fact, they are 



